Design and fabrication of composite smart structures for communication, using structural resonance of radiated field

In this paper we report the development of a loadbearing outer surface that enhanced antenna performances, and is termed CSS for 'composite smart structure'. A CSS is a multilayer composite sandwich structure in which antenna layers are embedded. Two types of CSS are designed. One uses a direct-feeding stacked patch antenna and the other an aperture-coupled patch antenna for electrical performances. The design procedure is presented including structure design, material selection and design of antenna elements in order to achieve high electrical and structural performances. Antenna design is processed at a central frequency of 12.2 GHz and a bandwidth over 1 GHz. Honeycomb thickness under the outer facesheet is selected for the most efficient electrical performances. A high gain can be obtained by placing an outer facesheet at a resonance position of the radiated field, which is half the wavelength distance from the spot which the radiation originates from. Measured electrical performances show that CSSs have a wide bandwidth over 10% and a higher gain than the antennas before they are embedded, and no doubt they have excellent structural performances due to sandwich effects by composites and honeycomb cores. With the CSS design concept, antenna efficiency can be improved with structurally effective materials of high electrical loss. The CSS concept can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers, promising innovative future communication technology.